51 results about "Conductance method" patented technology

The invention discloses a compound vacuum gauge calibration system and method, belonging to the technical field of measurement. The compound vacuum gauge calibration system disclosed by the invention comprises a mechanical pump, a molecular pump, a first vacuum valve, a second vacuum valve, a third vacuum valve, a fourth vacuum valve, a fifth vacuum valve, a sixth vacuum valve, a seventh vacuum valve, a vacuum gauge, a capacitance diaphragm gauge, a third vacuum gauge, a calibration chamber, a first small hole, a second small hole and an air source. The invention further discloses a compound vacuum gauge calibration method; a capacitance diaphragm gauge of which the full range is 1000 Torr is adopted as reference standard; the direct comparison method is adopted to realize the calibration within the range of 10<5> to 100 Pa; the expansion method is adopted to realize the calibration within the range of 100 to 10<-3> Pa; and the dynamic flow conductance method is adopted to realize the calibration within the range of 10<-4> to 10<-6> Pa. The compound vacuum gauge calibration system disclosed by the invention has the characteristics of low cost, small weight and size, portability, and the like.

The invention discloses a solar maximum power tracking method, which comprises the following steps of: firstly, carrying out global optimizing by using a larger-step-length disturbance method, finding a global maximum power point, tracking the maximum power point by using an incremental conductance method, and absorbing the advantages of the two methods to ensure the correctness of the current maximum power point; and secondly, locking the found maximum power point for eight to ten minutes, and searching the maximum power point for the second time after eight to ten minutes. The invention also discloses a charging device by using the solar maximum power tracking method. A control end of a buck type conversion module of the charging device is connected with a maximum power point tracking (MPPT) core control module; a signal input end of the buck type conversion module is connected with a solar battery; and a signal output end of the buck type conversion module is connected with a storage battery. By the invention, the charging efficiency of the solar battery on the storage battery is improved.

The invention discloses a measuring method of carbon, hydrogen and nitrogen contents in biomass fuel. The measuring method comprises the following steps of burning a sample to be measured, collecting mixed gas generated by burning, measuring and calculating full carbon, full hydrogen and full nitrogen percentage contents of the sample to be measured, and calculating the carbon, hydrogen and nitrogen contents in the biomass fuel to be measured. The method has the advantages that the measuring accuracy of the method is higher than that of an infrared-thermal conductance method of a coal sample, the measuring efficiency of the method is higher than the combined measuring efficiency of standard measuring methods, namely a semimicro Kelvin method and a three-section furnace method, and the method is applicable to quickly and efficiently measuring the carbon, hydrogen and nitrogen contents in the biomass fuel, can achieve high accuracy of measuring results and is low in implementation cost.

The invention discloses a photovoltaic power generation system environment self-adaptive type MPPT (maximum power point tracking) method. A voltage correcting parameter delta U and PI are introduced to control a link, a duty ratio D of a direct-current chopper is regulated in real time, maximum power point voltage Um optimal-searching speed is increased, the power loss is reduced, and the maximum power point voltage Um is changed in real time along with the environmental conditions, the incremental conductance method (I&S) optimal-searching step length is reduced, and the photovoltaic battery MPPT is quickly and accurately realized, the defects that a conventional MPPT algorithm is easy to affect by the environment, the robustness is poor and the power loss is relatively large are improved, and the defects that the intelligent type MPPT algorithm is complex and easy to be locally optimal are also avoided.

The invention relates to a system and a method for detecting a polymerase chain reaction (PCR) process through a non-contact conductivity method in rear time. The system is characterized by comprising an integrated PCR microchip based on micro-electromechanical system (MEMS) integration, an alternating-current excitation power supply, a current-to-voltage converting and amplifying circuit, a temperature sensing circuit, a heating circuit, a digital-analog/analog-digital conversion interface DAQ and an upper Labview control center, wherein the integrated PCR microchip integrates a micro reaction cavity, a temperature sensing electrode, a heating electrode and an electrochemical detection electrode; the micro reaction cavity is etched on the front surface of a silicon substrate; the heating electrode and the temperature sensing electrode are integrated on the back surface of the silicon substrate; the electrochemical detection electrode is an interdigital electrode, is bonded with the silicon substrate through an insulating layer and forms a sealed structure with the micro reaction cavity; and temperature circulation required by amplification is realized through the temperature sensing electrode and the heating electrode which are arranged on the back surface of the silicon substrate. The sensitivity and the resolution ratio of the system provided by the invention can reach fg/muL below, the reusability of the electrodes is high, the service life is long, and the reliability of the detecting result is high.

The invention relates to a device for measuring an extremely-low gas flow based on the static expansion vacuum standard. The device comprises a backing pressure measurement system, a first valve, a gas pressure relief system, a second valve, a calibration chamber, a third valve, a small hole, a fourth valve, a fifth valve, a getter pump, a sixth valve, a molecular pump, a backing pump and an ionization gauge, wherein the backing pressure measurement system is connected with the gas pressure relief system through the first valve, the gas pressure relief system is connected with the calibration chamber through the second valve, the small hole is connected in parallel with the fourth valve to form a parallel structure and then one end of the parallel structure is connected with the calibration chamber through the third valve and the other end of the parallel structure is connected with a vacuum system, the getter pump is connected with the calibration chamber through the fifth valve, the backing pump is connected in series with the molecular pump and then connected with the calibration chamber through the sixth valve, and the ionization gauge is directly connected on the calibration chamber. The invention adopts the gas pressure generated by the static expansion vacuum standard to replace the introduced gas pressure of the gas flow meter in the constant conductance method, so as to further improve the gas flow measurement accuracy.

The invention discloses a device and a method for measuring pumping speed of a micro vacuum pump through a constant conductance method flow meter. The device and the method can be used for realizing precise measurement on pumping speed of the micro vacuum pump. The constant conductance method flow meter can be used to generate micro flow, and also stable gas flow can be provided for a long time, so that the needed micro stable gas flow problem in measurement of the pumping speed of the micro vacuum pump is solved; and meanwhile, a general method for measuring an up-down symmetrical structure of a test cover for ultrahigh vacuum pump pumping speed test is avoided, the inner surface area of the test cover is reduced, gas release influence quantity of the surface area of the test cover is reduced, test accuracy is improved, and accurate measurement for pumping speed of the micro vacuum pump is realized.

The invention relates to a device and a method for the online measurement of the residence time distribution of a rotating packed bed, belonging to the technical field of the online determination of the residence time distribution. The device comprises an electrode and an internal pipe, wherein the electrode is installed on the internal side and the external side of the non-conductive packing of the rotating packed bed, and the internal pipe is filled with tracer liquid. The electrode is connected with a slip ring through a conducting wire. The slip ring and a rotating shaft rotate synchronously and the slip ring is connected with a data acquisition system. The method is that gas and liquid with fixed flow are injected into the liquid distributor of the rotating packed bed, the tracer liquid is filled, the slip ring transmits electrical signals to the outside, electric signal data is acquired and residence time distribution function E (t) is obtained by adopting data integral calculation. The invention realizes the online measurement of the residence time distribution and has the advantages of that the real-time performance is high, the continuity is good, the detailed features ofliquid holdup can be comprehensively reflected and the like; and by adopting the conductance method, not only the error caused by the x-ray method, the ultrasonic method, the conductivity method andthe fluorescence method is overcome, but also the online measurement can facilitate the detection of the impacts of all kinds of impact factors of the residence time distribution on the liquid holdup.

The invention discloses a Bezier-based polynomial photovoltaic array maximum power tracking method. The method includes: during the process of measuring actual irradiance and temperature value of a photovoltaic array, calculating maximum power point parameter of a photovoltaic array, acquiring an output characteristic curve of the same, and performing polynomial fitting to obtain a fitting result;according to an incremental conductance method and voltage and current measured in real time, slightly adjusting a maximum power point acquired through theoretical calculation, and taking a voltage value acquired by detection as an independent variable to enable working output characteristics of a photovoltaic module to be at maximum power point voltage after slight adjusting and to enable the photovoltaic module to work at maximum output power to realize maximum power tracking of the photovoltaic array. The method can realize effective maximum power tracking and has the advantages of being simple to realize and high in tracking accuracy.

The invention discloses a tracking method for a maximum power point (MPP) of tandem photovoltaic modules. The tracking method comprises the following steps of globally scanning by taking open-circuit voltage as starting voltage; dividing a multi-peak P-U curve into single-peak P-U intervals according to output voltage of the tandem photovoltaic modules when bypass diodes are conducted; taking the P-U curve as a single-peak interval when no bypass diodes are conducted; introducing a formula delta U(n)=N*ln-dI(n+1)/dU(n+1)/[I(n+1)/U(n+1)] in absolute terms, calculating at 0.4 to 0.8 time of P-U intervals of all the single peaks to obtain a voltage value U0 when a linear equation value of delta U (n) about the output voltage U of the tandem photovoltaic modules is 0, and adopting an incremental conductance method to track the MPP by taking the U0 as starting voltage and the delta U (n) as a step length voltage value; comparing to obtain global MPP and working voltage. According to the tracking method disclosed by the invention, the quickness and the accuracy of tracking the MPP by the tandem photovoltaic modules can be guaranteed, and the effect of reducing power oscillation and loss of a circuit can be guaranteed.

The invention discloses a device and a method for measuring the pumping speed and the outgasing rate of an ionization gauge, more particularly a device and a method for realizing the measurement of the pumping speed and the outgasing rate of an ionization gauge by adopting gas micro-flow technique, belonging to the technical field of measurement. The device is composed of a flow meter, a variable flow pilot valve, a measured ionization gauge, a reference gauge, an upper vacuum chamber, a flow limiting pore, a lower vacuum chamber and a gas pumping unit. According to the invention, the known gas flow is offered by a gas micro-flow meter in a constant conductance method, achieving wide measurement range of the flow and small uncertainness of the measurement; and the pumping speed and the outgasing rate of the measured ionization gauge can be computed accurately.

The invention discloses an improved incremental conductance method for realizing maximum power point tracking of a solar cell. In the improved incremental conductance method, an operation work zone of the solar cell is judged according to the acquired output voltage and power of the solar cell, and different control modifying instructions are adopted according to different work zones so as to realize the maximum power point tracking of the solar cell. The improved incremental conductance method is characterized in that output voltage and current sampling of a disposal solar cell are increasedin an original MPPT (Maximum Power Point Tracking) scanning period, current variation caused by illumination change is eliminated by using an algorithm, thus the direction misjudgment generated by the incremental conductance method due to sharp change of the illumination intensity is avoided, and further the reliability of a maximum power point tracking system of the solar cell is improved.

The invention discloses a method for calculating and eliminating high-voltage insulation resistance measurement sampling circuit errors. The method comprises the steps that S2, two grounded divider resistors RT with the same resistance are set inside an insulation monitor mainframe; S4, bus grounded voltage VH and VL is obtained through the ground divider resistors, and the two ground divider resistors are represented through RH and RL; S6, when RH=RL=infinity, VH=VL=2,000 V; S8, when the system single-end ground or insulation resistance is lowered, an equation specified in the description isobtained. Due to the equation, the single-end ground resistance RH1 or RL1 can be obtained. For solving the problem that an existing detection technology error is large, a software algorithm based onthe electric conduction method is put forwards, the algorithm is simplified, the influence of the sampling resistor Rt for the measuring precision is considered, and the measuring precision is improved. The system insulation drop caused by positive and negative electrode ground voltage is prevented from being directly measured, and the requirement for the voltage sensor voltage level is lowered.

The invention discloses a double-sided printed circuit board (PCB) with elements and a mutual conductance method thereof, and provides a method for realizing mutual conductance by elements used in a double-sided PCB. The method comprises the following steps: providing the double-sided PCB with holes, wherein, the PCB comprises a top circuit layer, a bottom circuit layer and an insulating film layer bonded between the top circuit layer and the bottom circuit layer, and the holes pass through the top circuit layer and the insulating film layer besides the bottom circuit layer; optionally forming the bottom circuit layer at the holes to be aligned with or approximately aligned with the top circuit layer; and welding one part of the elements on the top circuit layer, and welding the other part of the elements on the bottom circuit layer at the holes so as to realize mutual conductance of the two circuit layers. The mutual conductance method is simple and low in cost; and double-sided circuits are conducted without eletcroless copper plating during the manufacturing process, thus being very environmental-friendly. The invention further discloses the PCB with the elements manufactured by the method.

The invention discloses a method for detecting the contents of carcinonitrile, quaternary ammonium salt and ammonium, potassium and calcium impurity ions thereof by adopting a cation exchange suppressed conductance method. The quaternary ammonium salt is N-(3-chloro-2-hydroxypropyl)-N,N,N-trimethylammonium chloride; the sample injection volume of a sample is 25[mu]L; after sample injection thereof, the sample is brought by an eluent into an IonPac CS 17 (4mm*50mm) guard column and an IonPac CS 17 (4mm*250mm) analytical column which are connected to an ion chromatograph for separation; 2mmol/Lof methanesulfonic acid is used as the eluent; at a flow rate of 1.0mL/min, conductance detection shows that the separation degrees of the carcinonitrile, 3-chloro-2-hydroxypropyltrimethylammonium chloride, NH4<+>, K<+> and Na<+> are greater than 1.5. By the method, the overall stability and the reproducibility are ideal and determination data are accurate and reliable; the method can be widely applied to food production, biomedicines and other industries.

The invention relates to a method and a device for the online measurement of the liquid holdup of a rotating packed bed, belonging to the technical field of the online measurement of the liquid holdup. The invention solves the problem that the existing liquid holdup measurement method is not suitable for the measurement of the liquid holdup of the rotating packed bed. The device comprises an electrode, wherein the electrode is arranged on the non-conductive packing of the rotating packed bed. The electrode is connected with a slip ring through a conducting wire. The slip ring and a rotating shaft rotate synchronously. The slip ring is connected with a data acquisition system. The steps of the method comprise that gas and liquid with fixed flow are injected into the rotating packed bed, the slip ring transmits electrical signals to the outside, the electric signal data is acquired and solution volume corresponding to the resistance of standard solution is compared. The invention realizes the online measurement of the liquid holdup and has the advantages of that the real-time performance is high, the continuity is good, the detailed features of the liquid holdup can be comprehensively reflected and the like; the method and the device can be directly used for the measurement of local liquid holdup; and by adopting the conductance method, not only the error caused by the weight method and the volumetric method is overcome, but also the online measurement can facilitate the detection of the impacts of all kinds of impact factors of the liquid holdup on the liquid holdup.

The invention relates to a variable-step photovoltaic MPPT optimization control method based on an incremental conductance method. According to the algorithm, the maximum power point of the photovoltaic array is tracked by automatically adjusting the step length through the distance to the MPP, the MPP can be quickly approached by using a large step size when being away from the MPP, and the step size is reduced when the MPP is approached so as to reduce jitter and improve precision until the photovoltaic cell finally runs at the maximum power point. When external illumination and temperature conditions change, the system can effectively track the global maximum power of the photovoltaic module due to the existence of the variable step size algorithm. According to the method, the stability of maximum power point tracking of the photovoltaic system is guaranteed, under the condition that current and voltage output changes are caused by sudden change of illumination and temperature, the tracking stability can still be improved under the condition that the speed is guaranteed, the phenomenon of misjudgment and misreading of maximum power tracking is avoided, and then long-term stable power output of the photovoltaic system is guaranteed.

The invention discloses a traditional Chinese medicine health state conductance main and collateral channel identification method and system. The method and system are suitable for being executed in computer equipment. The method includes the steps that main and collateral channel measured data of a testee is acquired; identification is carried out; an identification result is obtained; the physique of the testee is analyzed. The step of identification includes the steps of identifying the deficiency and excess condition of qi and blood of the testee, identifying the relative deficiency and excess condition of yin and yang of the testee, identifying the relative balance condition of the effects of the overall and main and collateral channels of the testee and identifying the upper and lower relative deficiency and excess condition of the testee. Human body bilateral twelve source acupoint measured values measured with a traditional Chinese medicine conductance method are identified, the measured result is calculated and analyzed, and the physique of the testee and the specific balance conditions of the overall and all the main and collateral channels, inner and outer, upper and lower, front and rear, and left and right are specifically identified according to the measured result of the specific testee.

The invention relates to a supersensitivity leakage detecting device with the lower limit being 10<-16> Pam<3>/s and a method. The supersensitivity leakage detecting device comprises a dry pump (RP1),a molecular pump (TMP1), a getter pump (NEG1), a vacuum gauge (G1), a four-stage mass spectrometer (QMS), a first vacuum valve, a second vacuum valve, a third vacuum valve, a fourth vacuum valve, a fifth vacuum valve, a detecting chamber (VC1), a constant conductance method flowmeter (FM), a gas source and a vacuum pipeline. According to the supersensitivity leakage detecting device, on the basisof a cumulative comparison method, the standard gas flow with the lower limit being 1.3*10<-16> Pam<3>/s is provided by the constant conductance method flowmeter, and thus the leakage detecting lowerlimit of the leakage detecting device is extended to 10<-16> Pam<3>/s.